AEM 30-4100 Users-Voltage Offset Issues (Solution)

[K24MR2]

I just wanted to put this info out there in the hopes that it may help someone else out. I'm using Kpro V3 on a stock K24A2. I was having issues getting Kmanager to read the same as my wideband gauge. My wideband is grounded the same location as my ECU, however I still required some voltage offset. According to the manual for the wideband, with the sensor unplugged, the voltage should read 2.35v and the gauge should display 14.7. I checked mine and it reads 2.6v and 14.8 with the sensor unplugged. I called AEM to ask them about this and was told it was normal, to trust what the gauge displays, and to simply adjust the voltage offset so my ECU reads the same as my gauge with the sensor unplugged. For me, this required -.2v offset. I was satisfied at the time with this answer but today I decided to do a test. I took the sensor out of my exhaust and sat it on top of a gas soaked rag. To my surprise, while my ecu and gauge read perfect around stoich, 14.7, as I expose the sensor richer, the gauge and ecu get further and further out of sync. This was disturbing to me because if anything, I want the gauge to read properly where it counts the most, from 12 to 13 AFR, where I want to be under full load. Even more important as I plan to turbocharge this motor soon and the rich end of the scale needs to be spot on. The solution I found was to set my voltage offset to 0, and change the Voltage/Lambda conversion table to .6v = 10 afr and 5v = 20 afr. Instead of what the AEM manual tells you, which is 0v =10 afr and 5v = 20 afr. I tested the wideband and it now reads perfectly in sync from full rich, 10 afr to 13 afr. At stoich it is about .2 afr out of sync, but to me that is not important. Hope this helps someone else out.

[K24MR2]

So... upon more testing, wideband still doesn't read correctly below about 11.5 afr. The ECU reads leaner than the guage, which is safer at least. It reads great between 11.5 to 13.5. Fucking piece just doesn't output a linear 0-5v signal, plain and simple. Will be switching back to Innovative next time.

[Spunkster]

I highly recommend the PLX Devices widebands.